U.S. patent application number 09/976291 was filed with the patent office on 2002-04-18 for method of and apparatus for making a tobacco rod.
Invention is credited to Heitmann, Uwe, Lorenzen, Heinz-Christen.
Application Number | 20020043268 09/976291 |
Document ID | / |
Family ID | 7659831 |
Filed Date | 2002-04-18 |
United States Patent
Application |
20020043268 |
Kind Code |
A1 |
Heitmann, Uwe ; et
al. |
April 18, 2002 |
Method of and apparatus for making a tobacco rod
Abstract
Apparatus for making one or more rod-like fillers of shredded
tobacco for use in the making of cigarettes or the like employs one
or two pneumatic conveyors having endless foraminous belts trained
over pulleys and including elongated stretches below communicating
parts of a common suction chamber. A shower of intermixed tobacco
shreds and smaller particles including tobacco dust and coarser
particles is directed against the undersides of the elongated
stretches. The shreds are attracted to and advance with the
respective belts to form streams which are ready to be trimmed and
thereupon draped into cigarette paper or the like. At least some
smaller particles penetrate through the respective belts into the
corresponding parts of the suction chamber. The contents of the
suction chamber are evacuated by suction and are returned to the
undersides of the elongated stretches of the belts for
classification. At least some coarser particles advance with the
belts and are incorporated into the respective streams of tobacco
shreds. The smaller particles enter the respective parts of the
suction chamber and are pneumatically conveyed to the main
dedusting unit of the cigarette making plant.
Inventors: |
Heitmann, Uwe; (Hamburg,
DE) ; Lorenzen, Heinz-Christen; (Wentorf,
DE) |
Correspondence
Address: |
VENABLE, BAETJER, HOWARD AND CIVILETTI, LLP
P.O. BOX 34385
WASHINGTON
DC
20043-9998
US
|
Family ID: |
7659831 |
Appl. No.: |
09/976291 |
Filed: |
October 15, 2001 |
Current U.S.
Class: |
131/84.3 ;
131/84.1; 131/84.2 |
Current CPC
Class: |
A24C 5/18 20130101; A24C
5/1835 20130101 |
Class at
Publication: |
131/84.3 ;
131/84.2; 131/84.1 |
International
Class: |
A24C 005/18 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 14, 2000 |
DE |
100 51 031.0 |
Claims
What is claimed is:
1. A method of building at least one stream of smokable material
from a mixture containing randomly distributed relatively large
first particulate material and randomly distributed relatively
small second particulate material including a coarser fraction and
a finer fraction, comprising the steps of: advancing the mixture
against one side of at least one moving belt forming part of a
pneumatic conveyor and having a permeability such that the belt
entrains the first material but permits at least some of the second
material to pass therethrough; thereupon at least partially
segregating the coarser an the finer fractions of the at least some
second material from each other; and admitting at least some of the
segregated coarser fraction into the entrained first material.
2. The method of claim 1, further comprising the steps of conveying
the segregated finer fraction of the at least some second material
in an air stream, and separating the finer fraction from the air
stream.
3. The method of claim 1, wherein the at least one belt moves in a
predetermined direction and said advancing step includes feeding
the mixture against the one side of the belt in the form of a
shower which is elongated in said predetermined direction.
4. The method of claim 1, further comprising the step of
establishing a suction chamber as a part of the pneumatic conveyor
at the other side of the at least one belt to atract the first
particulate material against the one side of the at least one
belt.
5. The method of claim 1, wherein said segregating step includes
directing at least some second material against the one side of the
at least one moving belt.
6. The method of claim 1, wherein said segregating step includes
directing the at least some second material against the first
material being entrained by the at least one moving belt.
7. The method of claim 1, wherein said admitting step includes
pneumatically conveying said at least some of the segregated
coarser fraction into the entrained first material.
8. The method of claim 1 of simultaneously building at least two
streams of smokable material, further comprising the step of
breaking up the mixture into at least two flows, said advancing
step including simultaneously advancing each of the at least two
flows against one side of one of at least two discrete moving belts
and further comprising the step of dividing the at least some
second material which has passed through the at least two belts
into at least two masses prior to said segregating step.
9. The method of claim 8, further comprising the step of
introducing each of the at least two masses into a different one of
the at least two streams.
10. The method of claim 1, wherein said advancing step includes
advancing the mixture against a relatively large first portion of
the one side of the at least one belt and said segregating step
includes directing the at least some second material against a
relatively small second portion of the one side of the at least one
belt so that the finer fraction passes through the at least one
belt and the coarser fraction moves with the at least one belt, and
evacuating the finer fraction at the other side of the at least one
belt.
11. The method of claim 10, wherein said evacuating step includes
entraining the finer fraction in an air stream and further
comprising the step of regulating the quantity of air in the air
stream to establish at the other side of the at least one belt a
constant subatmospheric pressure.
12. The method of claim 10, wherein the belt is arranged to move in
a predetermined direction and the at least some second material is
directed against the one side of the belt upstream of delivery of
first material, as seen in said predetermined direction.
13. The method of claim 1, wherein said segregating step includes
directing the at least some second material into the mixture
advancing against the one side of the at least one moving belt.
14. The method of claim 13, further comprising the step of
converting the entrained first material into a rod-like filler
including removing a first portion of the entrained first material
from a second portion at said one side of the at least one moving
belt, said directing step including admitting the at least some
second material into the second portion of the advancing first
material.
15. The method of claim 1, wherein the at least one moving belt is
arranged to move lengthwise in a predetermined direction and
further comprising the step of imparting to the at least some of
the second material a component of movement in said predetermined
direction prior to said admitting step.
16. Apparatus for building at least one stream of smokable material
from a mixture containing relatively large first particulate
material and relatively small second particulate material,
comprising: transporting means including a pneumatic conveyor
having an endless running belt including a first side and a second
side, and at least one first suction chamber adjacent one side of
said belt and having an outlet; means for feeding at least a
portion of the mixture against the other side of the belt opposite
said first suction chamber, said belt having a permeability such
that it entrains the first material but permits at least some
second material to pass into said chamber; means for evacuating
second material from the first suction chamber by way of said
outlet; means for admitting evacuated second material against at
least one of (a) said other side of said belt and (b) the first
material being entrained by the belt; at least one second suction
chamber disposed at said one side of said belt and arranged to
gather second material being furnished by said admitting means and
having passed through the belt due to suction in at least one of
said chambers; and means for drawing air and second material from
said at least one second suction chamber.
17. The apparatus of claim 16, wherein at least one of said
material admitting means and said means for drawing air and second
material comprises at least one air conveying conduit.
18. The apparatus of claim 16, wherein the volume of said at least
one first suction chamber greatly exceeds the volume of said at
least one second suction chamber.
19. The apparatus of claim 16, wherein said at least one peumatic
conveyor further includes means for moving said belt in a
predetermined direction, said at least one second suction chamber
being disposed upstream of said at least one first suction chamber,
as seen in said predetermined direction.
20. The apparatus of claim 16, wherein said at least one second
suction chamber is disposed in said at least one first suction
chamber.
21. The apparatus of claim 16, wherein said at least one pneumatic
conveyor further includes means for moving said belt in a
predetermined direction, said at least one second suction chamber
having a first length and said at least one first suction chamber
having a greater second length, as seen in said predetermined
direction.
22. The apparatus of claim 16, wherein said at least one pneumatic
conveyor further includes means for moving said belt in a
predetermined direction, said at least one second suction chamber
being spaced apart from said admitting means as seen in said
predetermined direction.
23. The apparatus of claim 16, wherein said means for admitting the
evacuated second material is arranged to discharge second material
into said feeding means.
24. The apparatus of claim 16, wherein said at least one pneumatic
conveyor further includes means for moving said belt in a
predetermined direction, said means for admitting the evacuated
second material being arranged to discharge second material with a
component of movement in said predetermined direction.
25. The apparatus of claim 16, further comprising means for
monitoring the pressure in said at least one second suction
chamber.
26. The apparatus of claim 16, further comprising means for
monitoring the pressure in said at least one first suction
chamber.
27. The apparatus of claim 16, further comprising means for
regulating the pressure in said at least one second suction
chamber.
28. The apparatus of claim 16, further comprising signal generating
first sensor means for monitoring the pressure in said at least one
first suction chamber, second signal generating sensor means for
monitoring the pressure in said at least one second suction
chamber, control means for processing the signals being generated
by said first and second sensor means, and means for adjusting said
air drawing means in response to signals being processed by said
control means.
29. The apparatus of claim 16, wherein said transporting means
includes two conveyors each having an endless foraminous running
belt and discrete second suction chambers for each belt, said
feeding means including means for dividing the mixture into two
fractions, and means for feeding a discrete one of said fractions
of the mixture against the other side of each of said belts, said
means for admitting including means for directing second material
toward the other side of the respective belt at least substantially
opposite the respective second suction chamber so that at least a
substantial part of the finer fraction of second material having
been directed against the other side of the respective belt is
drawn into the respective second suction chamber.
30. The apparatus of claim 29, wherein said means for admitting
further includes adjustable means for breaking up second material
into a plurality of discrete masses, one for each of said directing
means.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to improvements in methods of
and in apparatus for making tobacco rods. More particularly, the
invention relates to improvements in methods of and in apparatus
for making one or more continuous rod-like bodies, called fillers,
which can be converted into tobacco-containing parts of plain or
filter cigarettes, cigars, cigarillos or analogous smokers'
products.
[0002] It is well known to make the rod-like filler of a cigarette
by showering particles of tobacco (such as shreds of tobacco leaf
laminae) which is supplied by a so-called distributor or hopper
onto the exposed side of a running sieve-like endless foraminous
belt while the other side of the belt travels along the open side
of a stationary suction chamber. This results in conversion of the
shower into a stream which contains a surplus of tobacco particles
and moves lengthwise with the belt past a trimming or equalizing
device which removes the surplus. The resulting rod-like filler is
confined in a running continuous web of cigarette paper or other
suitable wrapping material to form therewith a continuous rod which
is severed at regular intervals to yield a succession of plain
cigarettes of unit length or multiple unit length. Such products
are ready to be confined in packs or to be provided with filter
mouthpieces to form therewith filter cigarettes of unit length or
multiple unit length. The making of plain or filter cigarillos,
cartridges, cigars or analogous smokers' products involves or can
involve procedures or steps similar to those involving the making
of plain or filter cigarettes. Conventional machines for the making
of plain and filter cigarettes are disclosed, for example, in U.S.
Pat. No. 4,281,670 granted Aug. 4, 1981 to Heitmann et al. for
"APPARATUS FOR INCREASING THE PERMEABILITY OF WRAPPING MATERIAL FOR
ROD-SHAPED SMOKERS' PRODUCTS".
[0003] It is also known to segregate particles of tobacco dust or
analogous less desirable fragments of smokable material from the
much more desirable elongated shreds of tobacco leaf laminae and/or
from the atmosphere in a cigarette making plant. The thus
segregated particles can be utilized for the making of sheets or
films of reconstituted tobacco. Alternatively, such less desirable
particles of dust or the like can be introduced into the tobacco
stream which is borne by the foraminous belt; such introduction
takes place prior to removal of the surplus, i.e., prior to
conversion of the tobacco stream into a rod-like filler. The
purpose of such introduction of tobacco dust and/or like
particulate material into the tobacco stream is to contribute to
the weight, bulk, density, "feel" and/or other desirable
characteristics of smokers' products embodying lengths of the
filler. It is normally preferred to remove all or practically all
particles of tobacco dust from the shower or showers of tobacco
particles (normally shreds) which are being conveyed to the
stream-forming station.
[0004] It is equally known to evacuate from the aforementioned
suction chamber of a cigarette rod making machine all or
practically all particles of tobacco dust. The term "dust" is
intended to embrace all such particles of tobacco and/or foreign
matter entrained by full-sized tobacco shreds which do or can
consist of a smokable material but are often too small to allow for
appropriate interlacing with genuine tobacco shreds. The thus
gathered particles of tobacco dust, as well as relatively small or
very small shreds, are admitted into the tobacco stream.
[0005] It is further known to simultaneously produce a plurality of
(particularly two) continuous cigarette rods each of which yields a
series of plain cigarettes of unit length. Reference may be had,
for example, to commonly owned U.S. Pat. No. 5,125,419 granted on
Jun. 30, 1992 to Heitmann for "METHOD OF AND APPARATUS FOR MAKING
PLURAL TOBACCO STREAMS". Such arrangement multiplies the output of
the cigarette making machine with two or more foraminous tobacco
rod making conveyors.
[0006] As a rule, the aforementioned suction chamber is adjacent
that side of an endless foraminous belt or the like which is
disposed opposite the side serving to gather a stream of tobacco
shreds. The suction chamber is apt to accumulate substantial
quantities of tobacco dust within a relatively short interval of
time. Such dust normally contains very small particles of tobacco
leaves which normally adhere to the adjacent tobacco shreds on
their way to the rod forming station but become separated from the
shreds during the next-following processing of cigarettes of unit
length or multiple unit length. The dust in the plenum chamber
further contains minute particles of sand and/or rock as well as
relatively small tobacco fragments which are more likely to be
interlaced with desirable tobacco shreds of standard size and/or
shape and which are less likely to readily penetrate through the
openings of the endless foraminous belt.
[0007] The relatively small tobacco fragments develop in part
during the making of tobacco shreds and in part during transport of
shreds from the shredding station to the rod forming station,
particularly during transport toward the foraminous belt. Some of
the small fragments even penetrate into the openings of the
foraminous belt and gather in the suction chamber. Additional
relatively small tobacco fragments develop during transport of
satisfactory shreds with the foraminous belt; thus, the end
portions of a certain percentage of shreds penetrate into the
openings of the belt to be sheared off the major portions of the
respective tobacco shreds during separation of the respective
portions of the tobacco stream from the foraminous belt.
[0008] In accordance with heretofore known procedures, all solid
particles which happen to penetrate into the suction chamber are
evacuated from the chamber with the air stream which enters the
chamber by way of openings in the foraminous belt, which flows
through the chamber, and which is evacuated by way of one or more
outlets. The thus evacuated air is caused to flow into a central
dedusting station of the entire cigarette making plant and the thus
accumulated mass of dust and minute or relatively small tobacco
shreds is thereupon converted into sheets or other configurations
of reconstituted tobacco. Such procedure must be carried out by
resorting to bulky and costly machinery and is expensive in spite
of the fact that the reconstituted tobacco can be or is being
reused for the making of smokers' products. For example, the sheet
can be shredded and the thus obtained shreds are admixed to the
shreds of the shower (i.e., to the shreds which are obtained as a
result of comminution of tobacco leaf laminae).
[0009] U.S. Pat. No. 3,282,270 (granted Nov. 1, 1966 to Morris et
al. for "TOBACCO-MANIPULATING APPARATUS") discloses a method which
involves segregation of tobacco dust directly at the cigarette rod
making machine and immediate pneumatic reintroduction of separated
dust into the shower of tobacco shreds advancing toward the
foraminous belt of the pneumatic conveyor which converts the shower
into a continuous tobacco stream. The introduction of dust into the
shower is to be carried out by the shreds which constitute the
shower, and retention of dust in the stream is to be effected by
those shreds which already adhere to the exposed side of the
foraminous belt.
[0010] A drawback of the just described patented proposal of Morris
et al. is that only the relatively large particles of dust are
intercepted by tobacco shreds at the foraminous belt. All or nearly
all small particles of tobacco dust, sand and other foreign matter
are free to reenter the suction chamber so that the air stream
issuing from the suction chamber contains a continuously increasing
percentage of dust and foreign matter. It is to be borne in mind
that the shower of tobacco shreds contains and delivers to the
tobacco stream forming station additional particles of tobacco
dust, sand and other minute particulate material and that, sooner
or later, all or nearly all such particles enter and circulate with
the air stream which delivers the solid contents of the suction
chamber to the shower of tobacco shreds advancing toward the
foraminous belt.
OBJECTS OF THE INVENTION
[0011] An object of this invention is to provide a method which
renders it possible to overcome the drawbacks of heretofore known
proposals to remove tobacco dust and other undesirable particles
from the mass of comminuted tobacco which is to be converted into
one or more rod-like fillers in a cigarette making machine or the
like.
[0012] Another object of the present invention is to provide a
novel and improved method which renders it possible to recover and
reuse acceptable fragments of smokable material which happen to
penetrate into the suction chamber(s) of a machine for the making
of one or more continuous tobacco-containing rods, such as a
cigarette rod making machine.
[0013] A further object of the invention is to provide a method
which reduces the likelihood or prevents the accumulation of large
quantities of tobacco dust and like minute particulate material in
the suction chamber(s) of a cigarette rod making or an analogous
machine for the making of smokers' products.
[0014] An additional object of the instant invention is to provide
a novel and improved method of achieving pronounced savings in
acceptable smokable material in a machine for converting one or
more showers of loose tobacco particles into one or more tobacco
streams ready for conversion into rod-like tobacco fillers in a
cigarette making or an analogous machine for the mass-production of
rod-shaped smokers' products.
[0015] Still another object of the invention is to provide a novel
and improved apparatus for the practice of the above outlined
method in cigarette rod making and analogous machines.
[0016] A further object of the invention is to provide an apparatus
which renders it possible to achieve substantial savings in
smokable material which is processed in a machine for the making of
cigarette rods and the like.
[0017] Another object of the invention is to provide an apparatus
which can be installed with equal advantage in a machine for the
making of a single continuous rod-shaped tobacco filler or for
simultaneously turning out a plurality of such rods.
[0018] An additional object of the invention is to provide a novel
and improved cigarette rod making machine.
[0019] Still another object of the invention is to provide a novel
and improved arrangement for treating tobacco dust and other small
particulate substances gathering in the suction chamber or chambers
of a cigarette rod making or an analogous machine.
[0020] A further object of the invention is to provide novel and
improved smokers' products wherein the rod-shaped smokable fillers
contain tobacco dust in a distribution superior to that in
presently known rod-shaped smokers' products containing recovered
tobacco dust and/or smokable particles of similar size.
SUMMARY OF THE INVENTION
[0021] One feature of our invention resides in the provision of a
method of building at least one stream of smokable material from a
mixture containing randomly distributed relatively large first
particulate material (such as standard-size shreds of tobacco leaf
laminae) and randomly distributed relatively small second
particulate material including a coarser or larger fraction and a
finer or smaller fraction. The coarser fraction of the second
particulate material can contain or consist of fragments of
standard tobacco shreds (such fragments develop in the tobacco
shredding machine and/or during travel of standard-size shreds from
the shredding machine into the distributor or hopper of a cigarette
maker and/or during transport from the hopper to the stream
building station). The finer fraction can contain tobacco dust
and/or minute fragments of tobacco shreds and/or foreign matter
(e.g., small particles of sand and/or the like).
[0022] The improved method includes a plurality of steps including
the step of advancing the mixture against one side of at least one
moving belt or band forming part of a pneumatic conveyor and having
a permeability such that the at least one belt intercepts and
entrains the first material but permits at least some of the second
material to pass therethrough. The belt preferably constitutes an
endless belt having an elongated lower reach or stretch the
underside of which is the aforementioned one side and the upper
side of which is adjacent the open underside of a suction chamber
which forms part of the pneumatic conveyor and attracts successive
increments of the mixture (such mixture can constitute an ascending
shower or column of randomly intermixed first and second
particulate materials) and causes the first particulate material to
adhere to the underside of and to advance with the lower reach of
the endless belt while permitting at least some of the second
particulate material to penetrate through the lower reach and to
enter the suction chamber. The method further comprises the steps
of at least partially segregating the coarser and finer fractions
of the at least some second material from each other (such step
follows the first step as well as the evacuation of the at least
some second material from the suction chamber), and of admitting at
least some of the thus segregated coarser fraction into the
entrained first material at the one side of the at least one
belt.
[0023] The finer fraction (or that part, if any, of such fraction)
which has passed through the belt for the second time is or can be
conveyed (e.g., in an air stream or another suitable carrier
medium) from the plenum chamber and is separated from the carrier
medium, e.g., in the central dust collecting plant of a cigarette
making factory. This ensures that the thus recovered finer fraction
cannot enter the atmosphere in the plant and can be put to use,
e.g., for the making of sheets or films of reconstituted
tobacco.
[0024] The at least one belt of the pneumatic conveyor is caused to
move lengthwise in a predetermined direction, e.g., past a station
at which the surplus of entrained first material is removed by a
suitable trimming or equalizing device so that the remaining part
of the mass of first material constitutes a continuous rod-like
filler ready to be draped into a web of cigarette paper or other
suitable wrapping or draping material. The advancing step of the
improved method preferably includes feeding the mixture against the
one side of the at least one belt in the form of a shower
(especially an ascending shower) which is elongated in the
predetermined direction so that the first material which is
directed against and is intercepted by the one side of the belt
forms an elongated tobacco stream which is ready to be trimmed and
to be thus converted into a rod-like filler.
[0025] The segregating step can include directing at least some
second material against the one side of the at least one moving
belt.
[0026] Alternatively or in addition to the just discussed
segregating step, the latter can comprise (or further comprise)
directing the at least some second material (i.e., the second
material which has already passed through the at least one belt)
against the first material which is being entrained by the at least
one belt. Otherwise stated, the admitting step can include
pneumatically conveying at least some of the segregated coarser
fraction into the entrained first material.
[0027] The advancing step of the improved method can include
advancing the mixture against a relatively large first portion of
the one side of the at least one belt, and the segregating step of
such method can include directing the at least some second material
against a relatively small portion of the one side of the at least
one belt so that the finer fraction passes through the at least one
belt and at least some of the coarser fraction moves with the at
least one belt, and evacuating the finer fraction at the other side
of the at least one belt. Such evacuating step can include
entraining the finer fraction in an air stream and the improved
method can further comprise the step of regulating the quantity of
air forming the air stream to establish at the other side of the at
least one belt a constant subatmospheric pressure. As already
mentioned above, the belt is arranged to move in a predetermined
direction (such as past the trimming or equalizing station), and
the at least some second material is preferably directed against
the one side of such belt upstream of the locus or loci of delivery
of first material.
[0028] The segregating step of the improved method can include
directing the at least some second material into the mixture
advancing against the one side of the at least one moving belt.
Such method can further comprise the step of converting the
entrained first material into a rod-like filler, and such
converting step can include removing a first portion (namely the
surplus) of the entrained first material from a second portion at
the one side of the at least one moving belt; the directing step
preferably includes admitting the at least some second material
into the second portion of the advancing first material, namely,
into the portion which, upon completion of the trimmig or
equalizing operation, constitutes the rod-like filler.
[0029] The improved method can further comprise the step of
imparting to the at least some of the segregated second faction a
component of movement in the direction of lengthwise movement of
the mixture-receiving portion or reach of the belt; the segregated
second fraction is preferably imparted such movement prior to the
admitting step.
[0030] The improved method can be resorted to for simultaneously
building at least two streams of smokable material. Such method can
further include the step of breaking up the mixture into at least
two flows, and the advancing step then includes simultaneously
advancing each of the at least two flows against one side of one of
at least two discrete moving belts. Still further, such method
comprises the step of dividing the at least some second material,
which has passed through the respective one of the at least two
belts, into at least two masses prior to the segregating step. The
just described embodiment of the improved method can further
comprise the step of introducing each of the at least two masses
into a different one of the at least two streams.
[0031] Another feature of the present invention resides in the
provision of an apparatus for building at least one stream of
smokable material from a mixture containing randomly distributed
relatively large first particulate material (such as standard-size
shreds of tobacco leaf laminae) and relatively small second
particulate material (such as tobacco dust, small or very small
portions of tobacco shreds, particles of sand and the like). The
improved apparatus comprises at least one pneumatic conveyor having
an endless running belt (including a first side and a second side)
and at least one first suction chamber adjacent one side of the
belt and having an outlet, and the apparatus further comprises
means for feeding at least a portion of the mixture against the
other side of the belt opposite the first suction chamber. The belt
has a permeability such that it entrains the first material but
permits at least some second material to pass into the first
suction chamber. The improved apparatus also comprises means for
evacuating second material from the first suction chamber by way of
the aforementioned outlet, means for admitting the evacuated second
material against the other side of the belt and/or against the
first material being entrained by the belt, at least one second
suction chamber disposed at the one side of the belt and serving to
gather second material being furnished by the admitting means and
having passed through the belt due to suction in the at least one
second chamber, and means for drawing air and second material from
the at least one second chamber.
[0032] The material admitting means and/or the means for drawing
second material from the at least one second suction chamber can
comprise one or more air conveying pipes, hoses and/or analogous
conduits.
[0033] The volume of the at least one first suction chamber can
greatly exceed the volume of the at least one second suction
chamber.
[0034] The at least one pneumatic conveyor further includes means
(such as one or more driven pulleys) for moving the belt in a
predetermined direction, and the at least one second suction
chamber can be provided or installed upstream of the at least one
first suction chamber (as seen in the predetermined direction).
Alternatively, the at least one second suction chamber can be
provided in the at least one first suction chamber. The length of
the at least one first suction chamber can exceed (e.g., it can be
several times) the length of the at least one second suction
chamber, as seen in the predetermined direction. Furthermore, the
at least one second suction chamber can be spaced apart from the
material admitting means, again as seen in the predetermined
direction.
[0035] It is also possible to construct and install the means for
admitting the evacuated second material in such a way that it
discharges second material into the feeding means.
[0036] The means for admitting the evacuated second material can be
arranged to discharge second material with a component of movement
in the predetermined direction.
[0037] The apparatus can further comprise signal generating sensors
and/or other suitable means for monitoring the pressure in the at
least one first and/or in the at least one second suction chamber
and/or means for regulating the pressure in the at least one second
suction chamber. The regulating means can include control means for
processing signals being furnished by the aforementioned sensor
means and means for adjusting (when warranted) the air drawing
means in response to the processed signals.
[0038] If the improved apparatus is utilized in a machine for
simultaneously producing two or more rod-like fillers of smokable
material, the transporting means includes at least two conveyors
(each having an endless foraminous belt) and at least one second
suction chamber for each conveyor. The feeding means of such
apparatus includes means for dividing the mixture into several
fractions, one for each conveyor, and means for feeding a discrete
fraction of the mixture against the other side of the belt of each
conveyor. The means for admitting evacuated second material then
includes means for directing second material toward the other side
of the respective belt at least substantially opposite the
respective second suction chamber so that at least a substantial
part of the finer fraction of second material having been
discharged against the other side of the respective belt is drawn
into the respective second suction chamber. In such apparatus, the
means for admitting the evacuated second material against the other
side of the respective belt and/or against the first material being
entrained by the respective belt further includes adjustable means
for breaking up second material into discrete masses, one for each
of the directing means.
[0039] The novel features which are considered as characteristic of
the invention are set forth in particular in the appended claims.
The improved apparatus itself, however, both as to its construction
and the modes of assembling, installing and operating the same,
together with numerous additional important and advantageous
features and attributes thereof, will be best understood upon
perusal of the following detailed description of certain presently
preferred specific embodiments with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0040] FIG. 1 is a schematic partly elevational and partly
sectional view of an apparatus embodying one form of the present
invention and being designed for use in a machine which is set up
to simultaneously turn out a plurality of rod-shaped tobacco
fillers;
[0041] FIG. 2 is a enlarged fragmentary schematic sectional view of
a device which can be utilized in the apparatus of FIG. 1 to divide
a flow of segregated small particles of smokable material into two
discrete masses;
[0042] FIG. 3 is a similar view of a second device which can be put
to use in lieu of the device shown in FIG. 2;
[0043] FIG. 4 shows an apparatus which is somewhat different from
that shown in FIG. 1; and
[0044] FIG. 5 shows an apparatus which constitutes a simplification
of the apparatus shown in FIG. 1 or 4.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0045] FIG. 1 shows an apparatus which is designed to supply two
discrete rod-shaped fillers 43, 44 of smokable material (primarily
shredded tobacco leaf laminae) to two discrete wrapping mechanisms
of a cigarette making machine of the type disclosed, for example,
in aforementioned U.S. Pat. No. 5,125,419 granted Jun. 30, 1992 to
Heitmann for "METHOD OF AND APPARATUS FOR MAKING PLURAL TOBACCO
STREAMS". A cigarette making machine which can embody the apparatus
of FIG. 1 is known as PROTOS 2 (distributed by the assignee of the
present application).
[0046] The character 1 denotes a so-called distributor or hopper
which is set up to feed a mixture containing relatively large first
particulate material (such as customary tobacco shreds shown at 5a
and 6a) and relatively small second particulate material (such as
tobacco dust, particles of sand and/or metal and relatively small
(comminuted) tobacco shreds) into a duct 2. The latter feeds a
composite tobacco shower 3 containing the mixture of randomly
distributed large first and small second particulate material into
the range of a stationary separating tool 4 which divides the
shower 3 into two discrete narrower showers 5 and 6. The ascending
particles are attracted by a composite first suction chamber 15
having two sections or portions 15a, 15b each of which forms part
of a discrete pneumatic conveyor. The two conveyors serve as a
means for transporting the first particulate material and some of
the second particulate material from the distributor 1 to the
wrapping mechanisms of the machine embodying the improved
apparatus.
[0047] The first conveyor comprises an endless foraminous running
belt or strip 7 which is trained over pulleys 9 and 10. The
substantially horizontal lower reach or stretch of the belt 7
advances in the direction of arrow 13 when at least one of the
pulleys 9 and 10 is driven by a suitable prime mover, e.g., an
electric motor or the like. FIG. 1 shows a prime mover 9a which is
arranged to drive the front pulley 9.
[0048] The lower section 15a of the composite suction chamber 15
has an open underside adjacent the upper side of the lower stretch
or reach of the foraminous belt 7. This lower section of the
chamber 15 extends along the major part of the upper side of the
lower stretch of the belt 7. As shown in FIG. 1, the lower section
15a extends from the front pulley 9 toward but slightly short of
the rear pulley 10.
[0049] The construction of the illustrated upper pneumatic conveyor
is or can be identical with that of the lower conveyor. Thus, the
upper conveyor comprises an endless running belt or strip 8 which
is trained over two pulleys 11, 12 and is set in motion (note the
arrow 14) in response to starting of a prime mover 11a for the
pulley 11. It is clear that the prime mover 9a can drive the
pulleys 9, 11 of both pneumatic conveyors. The open underside of
the upper section 15b of the suction chamber 15 extends along the
upper side of the lower stretch or reach of the foraminous belt 8
all the way from the front pulley 11 toward but slightly short of
the rear pulley 12.
[0050] The shower 5 which is separated from the shower 3 by the
tool 4 ascends toward the underside of the lower reach of the belt
7 and its larger particulate material 5a is entrained in the
direction of the arrow 13. The thus accumulated stream of large
particles 5a is caused to advance past a conventional trimming or
equalizing device 16 which removes the surplus 45 but permits the
thus obtained rod-like filler 43 to advance into the aforementioned
wrapping mechanism which confines the filler 43 in an elongated
wrapper of cigarette paper or the like. Such wrapper and the filler
43 together constitute a continuous cigarette rod which is ready to
be subdivided into a row of plain cigarettes of unit length or
multiple unit length. The plain cigarettes are fed into a packing
machine or into a so-called tipping machine which latter assembles
the plain cigarettes with filter mouthpieces to form filter
cigarettes of unit length or multiple unit length.
[0051] The right-hand shower 6 shown in FIG. 1 is caused (by the
section 15b of the first suction chamber 15 and/or by a blower (not
shown) of the distributor 1) to rise toward the underside of the
lower reach of the endless belt 8 of the second pneumatic conveyor
further including the pulleys 11, 12 and the prime mover 11a. The
thus obtained stream (including the larger particles 6a) is
advanced (in the direction of arrow 14) past a second trimming or
equalizing device 17 which removes the surplus 46 but permits the
thus obtained rod-like filler 44 to advance into a second wrapping
mechanism wherein this filler is processed in the same way as the
filler 43.
[0052] A certain percentage of relatively small second particles
which are entrained by the larger particles 5a and 6a in the
showers 5 and 6 is advanced with the lower reaches of the belts 7
and 8. The permeabilities of the belts 7 and 8 are such that the
remaining relatively small second particles pass through the lower
stretches of these belts and advance in the respective sections
15a, 15b of the first suction chamber 15 toward the outlet 15c of
the section 15b. A suction generating material evacuating device 20
is set up to draw air and the remaining percentage 47 of the
relatively small particles through the outlet 15c, through a
conduit 18, and into a separator 19 which intercepts the solid
contents of the air stream flowing from the outlet 15c to the
device 20. The separator 19 can be a so-called Mahle
Industriefilter Type SFK 1560 distributed by Knecht Filterwerke
GmbH, hringen, Federal Republic Germany.
[0053] A conduit 21 conveys the separated solid material from the
separator 19 to a dividing means 22 which breaks up the separated
mixture of second particles into masses received by two discrete
conduits 23, 24 for delivery back to the respective pneumatic
conveyors.
[0054] The mixture 47 which is being evacuated through the outlet
15c of the section 15b of the composite plenum chamber 15 can
contain some or all (small or minute) particles of tobacco (tobacco
dust), sand or the like as well as a certain percentage of
fragmentized tobacco shreds (i.e., of fragmentized particles of
shreds of the type shown at 5a and 6a). The fragmentizing of shreds
can begin during advancement of shreds from the shredding machine
or machines into the distributor 1, during advancement of shreds in
the showers 5, 6 and/or on impact against the undersides of lower
stretches of the belts 7 and 8. For example, the end portions of
certain shreds forming part of the accumulations shown at 5a and 6a
penetrate into the openings of the belts and are broken off in
response to impingement of the exposed portions of such shreds upon
the accumulations 5a and 6a and/or vice versa. In accordance with a
feature of the present invention, at least the relatively large
fragments of tobacco shreds in the masses flowing through the
conduits 23, 24 are recovered and immediately or delayedly
introduced into the streams including the fillers 43, 44 and the
respective surplusses 45, 46. This entails substantial savings in
tobacco and contributes to the so-called fullness ("feel") of the
finished plain cigarettes.
[0055] The reintroduced material is shown at 50 in the tobacco
stream advancing with the underside of the lower stretch of the
belt 7, and at 51 in the tobacco stream advancing with the
underside of the lower reach of the belt 8. The distances between
the lower stretches of the belts 7, 8 and the rotary knives of the
respective trimming devices 16, 17 are such that the reintroduced
materials 50, 51 form part of the corresponding rod-shaped fillers
43 and 44. In other words, the reintroduced materials 50 and 51
form part of cigarette rods which are obtained as a result of
confining the fillers 43, 44 in webs of cigarette paper or other
suitable wrapping material.
[0056] The manner in which the dividing means 22 splits the mixture
47 into two masses which are returned to the respective pneumatic
conveyors (i.e., to the belts 7 and 8) will the described in full
detail with reference to FIGS. 2 and 3.
[0057] The character 25 denotes in FIG. 1 an ejector which can be
utilized in lieu of the dividing means 22 to expel solid particles
from an air stream in the conduit 21.
[0058] The means for admitting second material (mixture 47) against
the undersides of lower stretches of the belts 7, 8 and/or against
the streams of first material already adhering (by suction) to the
belts includes a total of four additional (second) suction chambers
28a (adjacent the upper side of the lower stretch of the belt 7 in
the lower section 15a of the first suction chamber 15), 28b
(adjacent the upper side of the lower reach of the belt 7 behind
the section 15a, as seen in the direction of the arrow 13), 29a
(adjacent the upper side of the lower reach or stretch of the belt
8 in the upper section 15b of the first chamber 15) and 29b
(adjacent the upper side of the lower stretch of the belt 8 behind
the section 15b, as seen in the direction of arrow 14). The second
suction chambers 28a, 28b, 29a and 29b are much smaller than the
suction chamber 15; in fact, the volume of each of the suction
chambers 28a, 28b is a small fraction of the volume of the section
15a, and the volume of each of the suction chambers 29a, 29b is a
small fraction of the volume of the section 15b. Furthermore, the
length of each of the second suction chambers 28a, 28b (as seen in
the direction of the arrow 13) is a small fraction of the length of
the section 15a, and the length of each of the second chambers 29a,
29b is a small fraction of the length of the section 15b (as seen
in the direction of the arrow 14).
[0059] The conduit 23 carries a material admitting nozzle 26a which
directs the recovered mixture of second particles against the
growing tobacco stream on the lower reach of the belt 7 in such
direction that some of the thus reintroduced (second) material is
propelled and/or is drawn toward the underside of the second
suction chamber 28a. A second material admitting nozzle 26b of the
conduit 23 discharges recovered second material in a direction
toward the underside of the lower reach of the belt 7 and against
the underside of the second suction chamber 28b.
[0060] The conduit 24 carries two material admitting nozzles 27a,
27b which respectively discharge second material against the
growing tobacco stream at the underside of the lower reach at the
belt 8 (as well as toward the underside of the suction chamber
29b). The means for drawing air and for thus evacuating the solid
contents of the suction chambers 28a, 28b by suction comprises
conduits 30a, 30b which discharge into a common conduit 32. The
latter discharges into a second suction generating device 35 which
segregates the solid particles from the gaseous carrier medium and
discharges such second particles into a suitable disposing or
processing unit 35a, e.g., into the central dust disposing or
dedusting or processing unit 35a of the plant or factory in which
the machine embodying the apparatus of FIG. 1 is being put to
use.
[0061] The means for evacuating the solid contents of the second
suction chambers 29a, 29b comprises conduits 31a, 31b leading to
the conduit 32 which delivers the solid particles to the
aforementioned suction generating device 35. The segregated solid
particles are admitted into the dedusting unit 35a.
[0062] The apparatus of FIG. 1 further comprises a control unit 39
which receives signals furnished by a pressure sensor 36 in the
second suction chamber 28a, by a pressure sensor 37 in the second
suction chamber 29a, and by a pressure sensor 38 in the upper
section 15b of the composite first suction chamber 15. The control
unit 39 processes the signals from the sensors 36, 37, 38 and, when
necessary, actuates the one and/or the other of the throttle valves
33, 34 or other suitable flow and/or pressure regulating means in
the respective conduits 30a, 31a. The conductors for the
transmission of processed signals from the control unit 39 to the
valves 33 and 34 are respectively shown at 40 and 41. A conductor
42 connects the control unit 39 with the suction generating device
35.
[0063] The nozzle 26a is installed in that portion of the duct 2
which guides the shower 5, i.e., the mixture of smaller particles
furnished by the conduit 23 can be fed directly into the shower 5.
Analogously, the nozzle 27a discharges second material directly
into the shower 6 advancing toward the underside of the lower reach
of the belt 8.
[0064] The apparatus of FIG. 1 can be set up to operate with the
nozzle 26a and/or 26b as well as with the nozzle 27a and/or 27b.
The actual positions of the second suction chambers 28a, 28b, 29a,
29b and of the associated nozzles 26a, 26b, 27a, 27b can be
different from those shown in FIG. 1, for example, if the shifting
of one or more nozzles to different position(s) renders such nozzle
or nozzles more readily accessible in a cigarette making machine or
an analogous machine embodying the apparatus of FIG. 1. The latter
shows the presently preferred positions of the nozzles and of the
associated second suction chambers. As a rule, there is sufficient
room between the distributor 1 and the belts 7 and 8 to accommodate
the nozzles 26a, 26b and 27a, 27b in a manner to render them
accessible for inspection, maintenance (such as cleaning) and/or
replacement.
[0065] The second chambers 28a, 28b are installed slightly
downstream of the respective nozzles 26a, 26b (as seen in the
direction indicated by the arrow 13), and the same applies for the
positions of the second chambers 29a, 29b relative to the nozzles
27a, 27b (as seen in the direction of the arrow 14). Therefore, the
inclinations of all of the nozzles 26a, 26b, 27a, 27b are such that
these nozzles discharge second material with components of movement
in the directions indicated by the respective arrows 13 and 14.
[0066] The apparatus of FIG. 1 can be operated with the nozzles,
26a, 27a, with the nozzles 26b, 27b, with the nozzles 26a, 27a and
26b, 27b, or even with a single nozzle (26a, 26b, 27a or 27b),
depending upon the percentage of small particles 47 in the showers
5 and 6 and/or upon the desired ratio of smaller particles to be
removed from the showers 5 and 6. In many instances, the apparatus
will be operated with the nozzles 26a or 26b and 27a or 27b open so
that at least some smaller particles will be withdrawn from the
shower 5 as well as from the shower 6.
[0067] The operation is as follows:
[0068] The distributor 1 of the cigarette rod making machine
delivers a wide tobacco shower 3 into the duct 2 wherein the tool 4
divides the wide shower into two narrower showers 5 and 6. The
showers 5 and 6 rise against the undersides of the lower reaches of
the respective foraminous belts 7, 8 where the larger particles 5a
and 6a accumulate to form two streams advancing in the directions
respectively indicated by the arrows 13 and 14. The stream
advancing with the belt 7 is equalized by the trimming device 16
which removes the surplus 45 but allows the thus obtained rod-like
filler 43 to advance toward the respective wrapping mechanism. The
stream advancing with the belt 8 is equalized by the trimming
device 17 which removes the surplus 46 but permits the thus
obtained rod-like filler 44 to advance with the belt 8 toward the
corresponding wrapping mechanism. Wrapping mechanisms which can be
utilized in combination with the apparatus of FIG. 1 are disclosed,
for example, in commonly owned U.S. Pat. No. 4,721,119 granted Jan.
26, 1988 to Ludszeweit et al. for "ROD MAKING MACHINE WITH MEANS
FOR ADJUSTING THE POSITION OF WRAPPING MATERIAL".
[0069] Suction in the composite first chamber 15 is selected in
such a way that the streams including the larger particles 5a and
6a are attracted to the respective belts 7, 8 as well as that at
least some smaller particles (shown in the upper section 15b of the
chamber 15, as at 47) penetrate through the respective belts and
flow with air toward and through the outlet 15c, i.e., into the
evacuating conduit 18. Such smaller particles 47 are part of the
streams 5 and 6 and penetrate through the growing streams at the
undersides of lower stretches of the belts 7 and 8 and enter the
respective sections 15a, 15b of the composite first suction chamber
15 to be evacuated with the stream of air flowing into the conduit
18 under the action of the suction generating device 20. The
separator or filter 19 intercepts the smaller particles 47 and
admits them into the conduit 21. The dividing means 22 breaks the
flow of particles 47 ito two masses which are respectively admitted
into the conduits 23 and 24.
[0070] If the nozzles 26a, 27a are open, they discharge the
respective portions 48, 49 of the mixture 47 into the respective
showers 5, 6 for entrainment toward the undersides of the lower
stretches of the respective foraminous belts 7 and 8. The coarse
fractions 50, 51 in the streams being entrained by the respective
belts 7, 8 contain the larger constituents of the masses flowing in
the conduits 23, 24 and being discharged by the respective nozzles
26a, 27a. Tobacco dust 52, 53 and other minute constituents of the
masses issuing from the nozzles 26a, 27a can be attracted in part
by suction in the respective sections 15a, 15b of the suction
chamber 15 but primarily by suction in the respective second
suction chambers 28a 29a and are withdrawn therefrom via conduits
30a, 31a to enter the dedusting unit 35a by way of the conduit 32
and suction generating device 35.
[0071] The particles 50, 51 constitute the coarser fractions of the
mixtures being discharged by the nozzles 26a and 27a, and the
particles 52, 53 constitute tobacco dust and other minute particles
of similar size. The streams of tobacco shreds at the undersides of
lower reaches or stretches of the belts 7, 8 intercept coarser
particles of the mixture 47, e.g., fragments of broken-up tobacco
shreds. Even though such coarser particles of the mixture 47
normally constitute or can constitute a relatively small percentage
of the shower 3 being supplied by the duct 2 of the distributor 1,
they nevertheless contribute significantly to the economy of
operation of the cigarette rod making machine embodying the
apparatus of FIG. 1. The smallest particles of the masses being
supplied to the nozzles 26a, 27a via conduits 23, 24 penetrate
through the respective tobacco streams and through the lower
stretches of the respective belts 7, 8 to gather (at 52 and 53)
primarily in the respective second suction chambers 28a, 29a. Such
particles are evacuated into the dedusting unit 35a via conduits
30a, 31a, 32 and suction generating device 35.
[0072] If the nozzles 26a, 27a are closed but the nozzles 26b, 27b
are free to discharge those portions of the mixture 47 which are
respectively delivered by the conduits 23 and 24, at least some of
the coarser fractions of the mixture 47 are intercepted and
entrained by the lower reaches of the belts 7, 8 (for addition to
the respective streams 43+45 and 44+46, and the finer fractions
(corresponding to those shown at 52, 53) are permitted to penetrate
into the second suction chambers 28b, 29b.
[0073] The signals from the pressure sensors 36, 37, 38 are
processed by the control unit 39 which (when necessary) initiates
an adjustment of the valves 33 and 34 in order to increase or
reduce the quantities of fine particles 52, 53 entering the
dedusting unit 35a accordingly. Additional pressure sensors can be
provided in the second suction chambers 28b, 29b for evacuation of
larger or smaller quantities of finer or finest particles via
conduits 30b, 31b when the nozzles 26a, 27a are closed but the
nozzles 26b, 27b are free to discharge minute particles received
from the respective conduits 23, 24. The valves mounted in the
conduits 30b, 31b are not shown in FIG. 1.
[0074] It is also possible to open the nozzles 26a, 27a
simultaneously with the nozzles 26b, 27b, to open three of the four
nozzles, or to open only one of the four nozzles. This depends upon
the composition of the shower 3 and/or upon the desired percentage
of finer particles being admitted into the dedusting unit 35a.
[0075] The control unit 39 can be set up to operate the valves 33,
34 and the suction generating device 35 (via conductors 40, 41 and
42) in such a way that there are no abrupt changes of pressure at
the boundaries between the second chambers 28a, 29a and the
respective sections 15a, 15b of the first suction chamber 15.
[0076] The means 22 for dividing the second particles 47 being
delivered by the conduit 21 into two masses which enter the
conduits 23, 24 can be constructed and operated in a manner as
shown in FIG. 2 or 3. FIG. 2 shows a conduit 102 (corresponding to
conduit 21 shown in FIG. 1) which supplies a stream of air and the
particles 47 into a dust separator 101. Cleaned air is evacuated
via conduit 103, and a gate 104 transfers the separated solid
particles 47 into a collecting receptacle 105. The latter is
provided with ejectors 108, 109 which respectively deliver
particles to the conduits 110, 111 corresponding to the conduits
23, 24 shown in FIG. 1. A pivotable partition 106 is provided to
distribute the particles entering the receptacle 105 between the
ejectors 108 and 109, i.e., between the conduits 110 and 111. A
handgrip portion 107 (e.g., a lever) is provided to select the
angular position of the partition 106 and hence the ratios of solid
prticles leaving the receptacle 105 and entering the ejectors 108,
109. The gate 104 can include or constitute a cell wheel which is
rotatable about a fixed axis and has vanes or blades which transfer
solid particles from the dust separator 101 into the collecting
receptacle 105.
[0077] The manually operable handgrip portion 107 can be replaced
with an electric motor or with any other suitable automatically
operable device capable of properly selecting the positions of the
partition 106.
[0078] The structure which is shown in FIG. 3 constitutes another
presently prefered version of the separator or dividing means 22. A
pneumatic conduit 201 (corresponding to the conduit 21 in the
apparatus of FIG. 1) supplies a mixture (corresponding to the
mixture 47 shown in FIG. 1) of finer and coarser smaller particles
to a branch 206 serving to establish a connection between the
discharge end of the conduit 201 and the intake ends of two
conduits 202, 203 corresponding to the conduits 23, 24 shown in
FIG. 1. A pivotable flap 204 at the junction of the conduit 201
with the conduits 202, 203 has an end portion 205 extending into
the conduit 201 and serving to determine the distribution of the
mass of particles arriving via conduit 201 into the masses of
particles being admitted into the conduits 202 and 203. The flap
204 can be pivoted by hand (as in the embodiment of FIG. 2) or
automatically, e.g., by an electric motor receiving signals from a
control unit, not shown in FIG. 3.
[0079] FIG. 4 illustrates an apparatus which constitutes a
modification of the apparatus shown in FIG. 1. The main difference
between these apparatus is that, in FIG. 4, the nozzles 26a, 27a
and the corresponding second suction chambers 28a, 29a are omitted.
The suction chambers 28b, 29b of FIG. 4 respectively contain fluid
pressure sensors 36, 37 which transmit signals to the control unit
39. In all other respects, the apparatus of FIG. 4 is or can be
identical with the apparatus of FIG. 1. The particles which are
supplied by the nozzles 26b, 27b are classified only by the lower
reaches or stretches of the respective foraminous belts 7, 8.
Larger particles (such as acceptable-size fragments of tobacco
shreds) are entrained by the respective belts 7, 8 to be admixed to
the materials of the showers 5 and 6, respectively. The smallest
particles (such as tobacco dust) penetrate through the belts 7 and
8, enter the second suction chambers 28b, 29b, respectively, and
are evacuated by the suction generating device 35.
[0080] As a rule, the tobacco shower 3 furnished by the distributor
(such as 1) of a cigarette rod making machine contains a relatively
low percentage (e.g., about 5%) of small tobacco particles. It has
been ascertained that the weight of such small tobacco particles
approximates 50 kg per 8-hour shift per cigarette making machine. A
substantial percentage of small tobacco particles consists of
useful fragments of tobacco shreds, i.e., of smokable material
which can form part of the stream including the rod-like filler 43
or 44. The remaining percentage of small tobacco particles consists
of tobacco dust and fragments of mineral substances (such as sand).
Under ideal circumstanes, only tobacco dust, sand and like minute
particles would be permitted to enter the chamber 15 to be
evacuated at 15c, separated from the gaseous carrier medium at 19,
and prevented from reentering the shower 5 and/or 6 (and hence the
suction chamber 15).
[0081] If the segregated particles 47 (which contain tobacco dust,
sand as well as useful fragments of tobacco shreds) were simply
returned into the showers 5 and 6, at least a substantial
percentage of tobacco dust and sand would reenter the chamber 15 so
that the percentage of dust in this chamber would rapidly increase.
Repeated or continuous evacuation of air and dust at 15c would
produce a progressively increasing quantity of dust which would
circulate in the cigarette making machine. Added to the dust being
continuously delivered by the shower 3, the recirculated dust would
cause rapid overfilling of the machine with undesirable
material.
[0082] The purpose of the second suction chambers 28a, 28b, 29a and
29b is to prevent the accumulation of excessive percentages of dust
in the suction chamber 15. The second suction chambers are at least
substantially sealed from the respective sections 15a, 15b of the
first suction cxhamber 15, i.e., fine particles (such as 52 and 53)
cannot escape from the respective second suction chambers (such as
28a, 29a) except by way of the conduits (30a, 31a) leading to the
dedusting unit 35a via suction generating device 35. In other
words, the particles 52, 53 cannot be readmitted into the suction
chamber 15 because they cannot enter the conduit 21.
[0083] The only regions where small particles (such as sand and/or
tobacco dust) can be caused to advance from the second suction
chambers (such as 28a, 29a) into the first suction chamber 15 would
be along the open undersides of the chambers 28a, 29a, with the
respective foraminous belts 7, 8, and into the respective sections
15a, 15b of the first suction chamber 15. This is prevented (or the
likelihood of such advancement of sand and/or tobacco dust is
greatly reduced) by the simple expedient of regulating the pressure
(suction) in the chamber 15 so that this pressure equals or at
least approximates the pressure (suction) in the chambers 28a, 29a.
Such equalization of pressures prevailing in the chambers 15, 28a,
29a brings about the additional advantage that it prevents the
development of air streams flowing transversely and at the
undersides of lower reaches of the belts 7 and 8; such transverse
flows could affect the predictability of the buildups of tobacco
streams at the undersides of the belts 7 and 8. The aforediscussed
equalization of pressures can be achieved by appropriate
adjustments of the throttle valves 33, 34 and/or of the suction
generating device 35.
[0084] The undersides of the two sections 15a, 15b of the first
suction chamber 15 and of the second suction chambers 28a, 28b,
29a, 29b communicate with the atmosphere by way of the lower
reaches of the belts 7 and 8, respectively. In addition, air which
enters the left-hand part of the section 15a and nearly the entire
section 15b must flow through the partially or completely built up
tobacco streams 43, 45, respectively. The nozzles 26a, 27a
respectively deliver the mixtures 52, 53 against the undersides of
the growing tobacco streams 43, 45 and 44, 46. Some fine fractions
(tobacco dust and sand) of such mixtures can penetrate through the
respective growing tobacco streams on their way into the sections
15a, 15b of the first suction chamber 15; however, the major parts
of such fine fractions are attracted into the respective second
suction chambers 28a, 29a and are evacuated therefrom via the
respective conduits 30a, 31a and into the dedusting unit 35a, i.e.,
they cannot reenter the chamber 15. On the other hand, the larger
fractions of the mixtures 48, 49 which are respectively delivered
by the nozzles 26a, 27a are intercepted by the respective growing
tobacco streams 43, 45 and 44, 46 to be entrained by the respective
belts 7,8 and to form part of the rod-like fillers 43, 44.
[0085] Since the second chambers 28a, 29a are at least
substantially sealed from the respective sections 15a, 15b of the
first suction chamber 15, any tobacco dust and/or sand entering the
chambers 28a, 29a is reliably prevented from reentering the chamber
15 so that the quantity of tobacco dust and/or sand in the chamber
15 does not increase in spite of recirculation of the mixture 47,
namely primarily into the second suction chambers 28a, 29a via
separator 19, conduit 21, dividing means 22, conduits 23, 24 and
nozzles 26a, 27a.
[0086] The efficiency of the improved apparatus is surprisingly
high in spite of the fact that any reusable smaller particles which
happen to enter the second suction chambers 28a, 29a are not
introduced into the tobacco stream 43, 45 and/or 44, 46. Thus, all
tobacco particles which enter the chambers 28a, 29a are admitted
into the dedusting unit 35a regardless of whether such particles
contain components which are sufficiently large to warrant or
justify introduction into the tobacco streams advancing toward the
respective trimming devices 16, 17. However, the total quantity of
useful tobacco particles in the accumulations 52 and 53 in
comparison with those delivered by the showers 5 and 6 is very
small or even negligible. The main reason is that the lengths of
the second suction chambers 28a, 29a in comparison with those of
the sections 15a, 15b (as seen in the directions respectively
indicated by the arrows 13 and 14) are small or negligible.
[0087] It is to be borne in mind that the likelihood of entry of
useful short or small tobacco particles (such as fragments of
tobacco shreds) into the second chambers 28a, 29a, i.e., of a
renewed penetration of such useful particles through the openings
of the belts 7 and 8, is extremely low. For example, if the
likelihood of penetration of reusable tobacco particles through the
belts 7 and 8 to form part of the particles 47 is 10%, the
likelihood of penetration of such particles (supplied by the
nozzles 26a, 27a) into the second suction chambers 28a, 29a to form
part of the mixture 52 and/or 53 is not more than 1%, i.e., about
99% of particles 52, 53 consist of tobacco dust and/or sand.
[0088] The preceding observations apply with equal or similar force
for the mixtures which are supplied by the nozzles 26b, 27b against
those portions of the belts 7, 8 which are not located below the
sections 15a, 15b of the first suction chamber 15. Thus, the
particles which enter the second suction chambers 28b, 29b (when
the nozzles 26b, 27b are utilized or provided in the apparatus of
FIG. 1) consist practically exclusively of tobacco dust and/or sand
so that they need not be classified again but can be readily
admitted (via conduits 30b, 31b) into the second suction generating
device 35 and thence into the dedusting unit 35a.
[0089] It is possible that some of the particles which are supplied
by the nozzles 26a, 27a bypass the respective second chambers 28a,
29a and reenter the respective sections 15a, 15b of the first
suction chamber 15. It has been ascertained that the percentages of
such particles (in comparison with those being supplied by the
conduits 23 and 24) are small, negligible or actually or
practically nil. Therefore, such possibility of undesirable passage
of certain small particles (e.g., sand and/or tobacco dust) through
the chamber 15 can be disregarded.
[0090] A comparison of the lengths of suction chamber sections 15a,
15b (as seen in the directions respectively indicated by the arrows
13 and 14) indicates that, in the absence of any undertakings to
the contrary, the section 15a would be much more likely to receive
substantial quantities of gaseous carrier medium than the section
15b. This could affect the pressures in the chamber sections 15a
and 15b. The reason is that a substantial portion of the lower
reach of the belt 7 is not overlapped by a growing or fully grown
tobacco stream so that, in the absence of an effective undertaking
to the contrary, suction in the section 15a could be well below
that which is required to properly advance the tobacco stream
43+45. In order to facilitate proper regulation of air pressure in
the chamber section 15a, the corresponding portion of the upper
side of the lower reach of the belt 7 is overlapped by a panel, a
sheet or an analogous air flow impeding device 15d which can be
made of a plastic or other suitable material.
[0091] It is desirable to utilize an air flow impeding device 15d
which does not completely prevent the flow of air therethrough,
i.e., it is advisable to employ a device 15d which is sufficiently
permeable to ensure that the suction prevailing in the chamber
section 15a can attract acceptable smaller tobacco particles (such
as fragments of tobacco shreds) issuing from the nozzle 26b when
this nozzle is utilized in lieu of or in addition to the nozzle
26a. An air flow impeding device is not necessary at the nozzle 27b
because the building zone for the stream 44+46 begins at the second
suction chamber 29b. The device 15d replaces sealing devices which
are utilized in certain conventional machines to completely block
the flow of air through the adjacent portion of a foraminous
belt.
[0092] By employing the device 15d, the belt 7 in the apparatus of
FIG. 1 is capable of attracting relatively large tobacco particles
issuing from the nozzle 26b and of entraining such particles into
the actual tobacco stream building zone beginning at or even ahead
of the suction chamber 28a and extending therefrom in the direction
indicated by the arrow 13.
[0093] The air flow impeding device 15d can be omitted if the
suction which is generated by the device 20 is sufficiently
pronounced to ensure that the belt portion advancing between the
suction chambers 28a, 28b shown in FIG. 1 can entrain acceptable
tobacco particles from the orifice of the nozzle 26b to the
location beneath the suction chamber 28a. Alternatively, the device
15d can be utilized jointly with a suction generating device 20
which (if necessary or desirable) can adequately attract acceptable
tobacco particles issuing from the nozzle 26b so that such
particles advance with the lower reach of the belt 7 and on to the
tobacco stream building zone beginning at or even a little ahead of
the nozzle 26a.
[0094] FIG. 5 shows an apparatus constituting a further
simplification of the apparatus shown in FIG. 1 and a
simplification of the apparatus shown in FIG. 4. This apparatus is
designed for use in a cigarette making machine having a single
wrapping mechanism, namely for the rod-like tobacco filler 44. The
separator 22 of FIG. 1 is not necessary, and the same holds true
for the conduits 23, 24, i.e., the conduit 21 delivers all
segregated smaller particles to the nozzle 27a.
[0095] All such parts of the apparatus shown in FIGS. 4 and 5 which
are identical with or analogous to those shown in FIG. 1 are
denoted by similar reference characters.
[0096] The improved apparatus can be modified in a number of
additional ways without departing from the spirit of the invention.
For example, the sensors 36, 37 and 38 can be omitted if the
apparatus of FIG. 1 is provided with means (not shown) for
intermittently or continuously withdrawing samples of the solid
particles gathering in the first suction chamber 15. The results of
examination of such samples can be utilized to adjust the valve 33
and/or 34 in order to select appropriate subatmospheric pressures
in the corresponding suction chambers.
[0097] Furthermore, the separator 19 can be dimensioned to separate
solid particles from a fluid carrier being supplied by the conduit
18 as well as by one or more additional conduits supplying fluid
laden with tobacco dust and/or fragments of tobacco shreds which
are to be separated from fluid (normally air) and admitted to the
stream(s) at the underside(s) of the lower reach of the belt 7
and/or 8. For example, the separator 19 can receive air from the
area surrounding the cigarette making machine which embodies the
structure of FIG. 1, provided that such air contains that
percentage of useful smokable material which warrants the
withdrawal of smokable material and its admission into one or more
tobacco streams (such as the stream including the components 43, 45
at the underside of the lower reach of the belt 7 and/or the stream
including the constituents 44, 46 at the underside of the lower
reach of the belt 8).
[0098] The separator 22 can be combined with the separator 19 so
that the conduit 21 can be omitted.
[0099] FIG. 1 shows that the widths of the flows of recovered
smaller particles issuing from the nozzles 26a 27a are mere
fractions of the widths of the corresponding showers 5, 6 (as seen
in the directions respectively indicated by the arrows 13 and 14).
This ensures that all of the particulate material issuing from the
nozzles 26a, 27a and passing through the respective growing streams
at the undersides of the lower reaches of the respective belts 7,
8, as well as through the respective belts, can be intercepted and
gathered by relatively small second suction chambers 28a, 29a. The
above applies with equal force for the nozzles 26b, 27b and the
respective suction chambers 28b, 29b.
[0100] It is normally desirable to ensure that only certain
categories (sizes) of particles contained in the mixtures 48, 49 be
introduced into the tobacco streams advancing with the lower
reaches of the belts 7 and 8. It is equally desirable to ensure
that the dedusting unit 35a receive only tobacco dust and particles
of a similar size. All this is accomplished in the apparatus of
FIG. 1 by directing the mixtures 48, 49 into the showers 5 and 6 so
that the segregation of reusable tobacco particles (such as
fragments of tobacco shreds) can begin in the showers 5, 6 and
continue at the respective stream building stations where the
acceptable tobacco particles are intercepted by the growing tobacco
streams and/or by the lower reaches of the respective foraminous
belts 7, 8. Those small particles which are admitted by the nozzles
26a, 27a and are drawn into the respective second suction chambers
28a, 29a are of proper size to be conveyed into the dedusting unit
35a. However, a certain percentage of such smaller particles is
intercepted by the respective tobacco streams and advances
therewith toward the respective trimming devices 16, 17. Supplying
of tobacco streams with a surplus (such as those shown at 45 and
46) is desirable and advantageous because, once the surplus is
removed, the remaining portions 43, 44 of the tobacco streams
invariably constitute two rod-like fillers having constant cross
sections throughout and being convertible into parts of cigarettes
having constant diameters and densities. Such parameters contribute
to the quality of the rod-shaped smokers' products.
[0101] In a standard cigarette making machine, the filler 43 or 44
constitutes about two thirds of the stream including the components
43, 45 or 44, 46 of the respective tobacco streams, i.e., the
trimming devices are normally positioned to remove surplusses 44,46
each of which constitutes one-third of the tobacco stream being
advanced by the respective belt 7, 8. As already mentioned above,
and as shown in FIG. 1, the recirculated (medium sized) tobacco
particles 50 and 51 are admitted into those portions of the tobacco
streams which ultimately constitute the rod-like fillers 43,
44.
[0102] Though it is possible to install the nozzles 26a, 27a in the
respective showers 5, 6 at a considerable distance from the
respective belts 7, 8, it is normally preferred to place such
nozzles close to or into immediate proximity of the undersides of
lower reaches of the respective belts 7, 8; this ensures that the
second suction chambers 28a, 29a can gather all or nearly all small
particles which should be delivered to the dedusting unit 35a. As
already mentioned hereinabove, the positions of the nozzles 26a,
27a relative to the respective second suction chambers 28a, 29a are
selected, at least to a certain extent, with a view to ensure that
the nozzles are readily accessible in a cigarette making or an
analogous machine which can employ apparatus of the present
invention. The selected orientations of the nozzles 26a, 27a (as
well as 26b, 27b) in such a way that the material issuing from
their orifices has a component of movement in the direction of the
arrow 13 or 14 ensure more satisfactory entrainment of small
tobacco particles by the tobacco streams accumulating at the
undersides of the lower reaches of the belts 7 and 8.
[0103] An important function of the control unit 39 and of the
associated sensors (including those shown at 36, 37 and 38) is that
it ensures the establishment of an at least substantially constant
pressure along the upper sides of lower reaches of the belts 7 and
8. This is achievable in a simple and efficient manner by
regulating the rate of evacuation of air via conduits 30a, 31a.
[0104] The widths of the second suction chambers 28a, 28b and/or
29a, 29b (as seen in the directions indicated by the respective
arrows 13, 14) preferably exceed the widths or the diameters of the
outlets of the respective nozzles 26, 27a and/or 26b, 27b. This
enhances the ability of the second suction chambers to gather the
small particles which are to be conveyed to the dedusting unit
35a.
[0105] It is clear that the two suction conveyors shown in FIGS. 1
and 4 need not be installed at two different levels and above each
other. For example, these conveyors can be installed at the same
level (see the aforementioned U.S. Pat. No. 5,125,419 to Heitmann).
Furthermore, and as already mentioned hereinabove, the apparatus of
FIGS. 1 and 4 can be utilized with practically any selected,
desired or required number of nozzles, e.g., only with the nozzles
26a, 27a, with a single nozzle (26a, 27a, 26b or 27b), with three
nozzles, or with four or more than four nozzles.
[0106] Without further analysis, the foregoing will so fully reveal
the gist of the present invention that others can, by applying
current knowledge, readily adapt it for various applications
without omitting features that, from the standpoint of prior art,
fairly constitute essential characteristics of the generic and
specific aspects of the above outlined contribution to the art of
making cigarettes or the like and, therefore, such adaptations
should and are intended to be comprehended within the meaning and
range of equivalence of the appended claims.
* * * * *